Con Coughlin is the Telegraph's Defence Editor and a world-renowned expert on global security and terrorism issues. He is the author of several critically acclaimed books. His new book, Churchill's First War: Young Winston and the fight against the Taliban, is published by Macmillan in London and Thomas Dunne Books in New York. He appears regularly on radio and television in Britain and America.

Pull the other one, Vladimir. Russia will never back military action against Syria

There's nothing Russian President Vladimir Putin likes more than to play mind games with his opposite numbers in the West which, given his background as a former KGB officer, he invariably wins. Which is why I believe it would be sensible to take his suggestion – made in an interview with Associated Press – that Russia may be prepared to back military action against Syria which a large pinch of salt.

From the outset of the Syrian crisis, Mr Putin has made it abundantly clear that he has no intention of allowing the West to undertake regime change in Damascus, where the Assad regime has been a loyal ally of the Kremlin for more than four decades.

This is partly due to the fact that the Russians feel they were conned over Libya, where a UN resolution aimed at preventing a humanitarian disaster somehow transmogrified into a mandate for regime change. The other factor driving Mr Putin's calculations is that Syria is the only country in the region that might be plausibly described as pro-Russian. When the West is seen to be extending its influence in areas such as the Gulf states the Russian president has no intention of allowing a valuable strategic asset to wither on the vine.

With world leaders due to assemble in St Petersburg for another meaningless G20 summit this week, Mr Putin no doubt deems it politic to make sympathetic noises about the Syrian crisis, where recent claims that the Assad regime has used chemical weapons against its own people has prompted calls for international action.

The Russians, of course, do not believe Washington's claims that the evidence shows "beyond any reasonable doubt" that the Assad regime was responsible for this atrocity. Why, they argue, would Assad, at a time when (with Russian help) he is winning Syria's brutal civil war, would he risk provoking international action by using weapons of mass destruction?

But in order to play the diplomatic game, Mr Putin is happy to suggest that Russia might be prepared to back military action if a) it is proven Assad was directly responsible for the chemical attack, and b) there is UN backing for such action.

And so far as the latter issue is concerned, Mr Putin knows that there is absolutely no prospect of the UN sanctioning such action – for the simple reason that the Russians will use their seat on the Security Council to veto it.